Ah yes, the final frontier. As is usual with these things, the truth is stranger than any science fiction novels you've read. Space is a fascinating place.
u/TheLichB*tch asked Reddit:
Here are some of those facts.
There's a large cloud of dust and gas near the centre of the Milky Way called Sagittarius B2. It contains a significant amount of alcohol -- non-drinkable forms, but also standard ethanol -- and also high levels of a compound called ethyl formate, which is used as a flavouring in raspberry flavoured things. It's also about 150 light years across, which is pretty damn big.
The centre of the galaxy smells like a giant raspberry daiquiri... maybe.
— the Sun is the size of an atom
— Alpha Centauri (the closest star) is 1 mm away
— our galaxy, Milky Way is 15 m (50 ft) across
— Andromeda galaxy is 360 meters (3 football fields) away
— the observable Universe is the size of the Earth
— it takes light 4 years to travel 1 mm (100 years to travel 1 inch)
The Milky Way, the galaxy in which our solar system resides, is home to at least 100 billion other planets, and up to 400 billion stars.
The Milky Way is just one of 100-200 billion galaxies in the observable sky.
The concept of voids has always been mind-bending to me. For those who aren't familiar - our universe is basically formed of galactic groupings called "clusters" and "filaments," depending on whether they are groupings or long strands. Voids are the space in between these groupings, and are essentially massive zones of near-total nothingness, with something like ten times fewer particles than even interstellar space.
If you snap a piece of metal in half in the vacuum of space it will weld itself back together seamlessly if you rejoin the pieces. The only thing that stops it from happening on Earth is because we have a pesky oxygen rich atmosphere that ruins everything cool. Except fire. Fire is cool.
Venus In Fur
My absolute favorite space fact are the wacky orbital parameters of Venus. It takes Venus longer to rotate once around its own axis (ie a day) than it does to orbit once around the Sun (ie a year). Imagine trying to make a calendar for living on that planet.
Incredible Amounts Of Nothing
Space is empty, like, really empty.
If you flew a spacecraft from one side of the galaxy to the other, what are the chances you run into something?
What is 'something'? If you go through the galaxy you're guaranteed to hit molecular gas, dust, and maybe up to pebble-sized objects or something. But if you mean hitting anything planet-sized or bigger, you have a 0% chance (within rounding errors).
Put another way, if the entire universe had stars as densely packed as they are in galaxies, you'd still have to travel all the way across the observable universe 6300 times before you'd expect to run into anything planet-sized or bigger by accident.
I'm Getting Seasick
Hold up your hands and clap them together.
Wait one second, then do it again.
If you could plot the distance between the first clap and the second clap, it would be more than 800 kilometers.
This is because the Earth is moving around the sun, the sun is moving around the center of the galaxy, the galaxy is moving through the Virgo Supercluster, and the Virgo Supercluster is barreling through the universe. When you add up all the velocities and compare the result to the cosmic microwave background (which is the closest thing we have to a universal frame of reference), it comes out to about 800 kilometers per second.
Sit still for an hour, and you'll travel farther than you'll ever walk in your life.
You Win, Jaws
Astronomer here! One thing I don't think we discuss enough lately is that sharks are older than Saturn's rings!
Explanation: recent research from the Cassini spacecraft indicate that Saturn's rings are, in fact, very young- as young as 100 million years old. (We can tell this because years of bombardment from essentially tiny soot particles would make the rings much darker than they currently appear. They definitely weren't around 4.5 billion years, the age of the Solar System.) Sharks, on the other hand, have been around ~450 million years. Ergo, sharks > Saturn's rings!
As for what caused the rings, it was likely an impact of some sort, and people are now arguing over the various details.Here is a simulation of one of my favorites, which involves a comet hitting a large icy moon. Pretty lucky for us though, because TBH Saturn would appear nowhere near as incredible without the rings!
Be A Friend To The Water
Water facts- in SPACE!
Ganymede, Europa, and Callisto are thought to have subsurface oceans larger than all the bodies of water on Earth put together. Not all together- individually!
This is because water tends to aggregate in the outer part of solar systems while they're forming. Celestial bodies out there might have formed with as much as 50% water ice by mass! Water is soluble in magma, so most water would be trapped in the mantle. As the mantle cooled, water is exsolved- but unlike Earth, which is close enough to the sun to maintain liquid water on the surface, these moons are past the frost line. Water on their surface froze, but tidal flexing and the heat from their cores caused massive subsurface oceans to form!
One possible exo-planet type is the ocean planet, sometimes referred to as a panthalassic planet. Such planets would actually have a harder time developing life than Earth! Oceans on Earth extend down around 11km at the deepest point- on a panthalassic planet they could extend down hundreds of kilometers! At such depths, even at high temperatures the pressure would still cause massive layers of ice to form- ice that might not even be cold! This would make the travel of important nutrients, like phosphorus, to the water nearly impossible. On Earth, these nutrients mostly come from runoff from the land, which would be impossible on an ocean planet.
Such planets would have atmospheres thick with water vapor, which would cause a strong greenhouse effect. If they were large enough to trap hydrogen and helium, they would in effect become warmer ice giants, like Neptune or Uranus!